Process of manufacture of a glass using natural silicates, such as micaceous minerals, asbestos, and the like



- the like,

UNITED STATES PATENT OFFlCE.'

PERCY BRDAJJIBENT CROSSLEY, 0F CALCUTTA, INDIA.

PROCESS OF MANUFACTURE OF A GLASS USING NATURAL SILICATES, SUCH AS MICACEOUS MINERALS, ASBESTOS, AND THE LIKE.

No Drawing.

T oaZZ whom it may concern Be it known that I, PERCY BROADBENT CRossLnY, a subject of His Majesty King George V, whose address is Messrs. Hoare Miller & Company, 5 Fairlie Place, Calcutta, British India, consulting chemist and metallurgist, have invented a rocess for the Manufacture of a Glass Using Natural silicates, Such as Micaceous Minerals, Asbestos, and

of which the following is a specification.

The object of my invention is to utilize waste micas, asbestos and the like for the manufacture of glass.

It is well known that micas, asbestos and the like are very wasteful minerals to mine, and that over 90% of the mica is rejected during the subsequent operations of dressing, cleaning, etc. Much mica has to be rejected owing to impurities, cracks, crossgrain or twining.

The object of this invention is mainly to use these otherwise waste micas and to utilize waste asbestos or the like minerals.

It will be quite understood, however, that I need not confine myself to the waste materials only. I

The value of mica for industrial purposes depends upon one or a combination of its addition to those possessed by 'thevn atural,

' for any purpose forwhich-the natural pure desired shape or form-by rolling, for

properties of flexibility, fusibility, non-conductibility with respect to heat and electricity, etc. Its usefulness is rather limited owing to its fragile and laminated nature. As an example of one of the defects due to the latter-"maybe mentioned the bad effect due to the absorption of water and oil.

The present invention is to utilize these waste, impure or otherwise commercially unsuitable materials forthe production of a. substancewhichmay be equal in value .to ithe best micas as far as the electrical, heat insulating properties, trans arency, etc., are

concerned, but which will. ave, under cer-' tain conditions, other valuable properties in minerals. This new substance may be used minerals are used. It possesses other advantages in that it may be wrought into any P mg. new. product may extruding, molding, casting" or wel Articlesmade from the transparency, non- Specification of Letters Patent.

be machined. This new material may be made to adhere tenaciously to metals.

In carrying out my process micaceous minerals, asbestos or the like are suitably sorted or graded. These materials are then disintegrated. I generally crush the prodnets to a powder, but, in the case of mica, I may if I prefer use it in the shape of fine scales or flakes, or even as small films or splittings.

The disintegration may be performed by any of the ordinary processes. In the case of the treatment of mica, films or splittings can be produced by subjecting the natural blocks, plates, etc., to the repeated application of heat followed by rapid cooling, 2'. 6., quenching in Water or other fluid.

After disintegration has been accomplished to the desired extent the impure varieties of the micaceous minerals, waste micas, asbestos or the to chemical or other processes to remove the impurities.

These impurities, which in the case of micas are almost invariably only present on, the surfaces of the films, flakes or particles of the powder, may be converted intoa soluble form and removed'from the material by lixiviation with water or with weak soluteriously affecting the minerals. The material may be subsequently washed and dried.

In certain localities micas are found in a powdered or disintegrated form of very pure quality which may not need any mechanical manipulation or further purification before being used in my process.

These materials are then intimately mixed with a solid solvent, the nature and prop-. erties, including color, of which are modified to suit the special requirements the finished product has to meet.

As examples of the solvents used may be mentioned glass, made by the admixture of powdered lass with suitable active substances, suclI as cobalt lead orother metallic oxids, boric acid, metallic horates orborosilicates and the like,having a melting point lower than the temperature at which micaceous minerals, asbestos or the like begin to efiioresce or part with their water. of hydration, the temperature ranging from that required to melt ordinary glass to one below like may be subjected that at which the natural silicates, such as mica or asbestos, begin to change their physical and chemical characteristics, a temperature up to about 900 centigrade being emvplo ed.

ccording tothe (present invention the mixture is then heate in a suitable furnace usually for a considerable length of time at a temperature below that atwhich the micaceous constituents will begin to eflioresce, so as to obtain the desired incorporation of the solvent with the materials whereby the mixture becomes, either wholly or partially,-transforr'ned into a viscid mass.

fThe mixture may then besubjected to mechanical manipulation as maybe found de- Lsirable to formit into its final shape, such as. rolling, forging, etc.

After the micaceous constituents have been heated for some time, as above described, they dissolve and form a solid solution. hls solid solution can thereafter, if so desired,

a be raised to a higher temperature than that at which the micaceous constituents generally efioresce without suffering decomposicaceous constituents beyond that which sodution. Such'excess modifies the physical.

tion. I may ifI prefer add an excess of miwould be suificient to form a saturated soproperties of the resultant product, and it would appear that such excess is desirable if the resultant product is to be capable ofbeing machined with ease. I

The temperature and the length of time the mixture is kept in the furnace depends upon the proportmn of the solvent used 'in the mixture, and also upon the chemical 4 composition pf thesame.

Itis generall only necessary to heat the mixture to slig tly above the temperature at which the solvent will melt. If the pro-' portion of the micaceous constituents im the mixture is large it is generally desirable to, raise the temperature sli tly higher than whenthe proportions of-t ese constituents'is small. Q

By a suitable modification of the propor-v \tions ofthe mixture and in the choiceofthe obtained.

' chemical composition of'the solvent, prodr ucts having the desired properties can be If-desired I may into molds. A

From the above my process bears a close analogy tocertain processes used in the manufacture of alloys" "com osed of metals having widely differentmelting points, such as 2' c and iron, which metals form a solid so ution without the iron, which meltsfataimuch'hgher temperature thanzinc', being raised an in temperature to cause it to li uefy.

" at By using a suitable quality 9 mic and a, d

will recogn ilred' that aaeaevs colorless solvent glass, a transparent prodnot can be obta ned By using coloring agencies the glass produced may be of any. color desired. Such glasses can be used for many piirposes for whichordinary glass is used. y product may be transparent, semi-transparent or opaque as desired. The

semi-transparent and opaque varieties have As this material can be .made 7 and also capable of.

has a large field of usefulness. in the domestic arts;

Its capacity enormously to the adaptability of the material for industrial purposes. I J

It will be uite understood that I do not confine myself to the exact methods de scribed above. 7

any reasonable Inodificationbf the same. For instance, I may if-I prefer use a molten bath of the solvent into which I could feed the micaoeous minerals or the like, the mass being agitated as necessary. '-Aiternately, I niay add the moltensolvent" to the mication. Any com ination of th th meth ods m ght be used. t

I may, however, um I q the place of powdered glass as the v base of my solvent glass. For instance, an

natural for being I machined adds other substances in ceous minerals and allow it to act'upon the toe uent mechanical'slmanipular or artificial silicate might be used-"which is found to be suitable. I might mica, particularly in the form of waste plroducts frommy own-processes. 1 r

Insteadofthe solvent glass made by the above process, Iinay use other solvents, such as certain fluxes-or glazesuse'din the manufacture of ceramic'ware, whi' hm be suit 31316 ,f01 this purpose,

Having. now particularly and J ascertained the nature-of n said invention heat the substance until; the 'mass becomes liquefied and can beca'stto a temperature between that at which said vitreous material melts and that at which the silicatev begins; to" 1os 'e"its'water of hydration; whereby the silicate is dissolved in the moltenvitreous material. V

a 2. The method ofinanufacturing glass which comprises-heating a mixture of glass ous material and a silicate of hi glifusibility' silicate of highfusibility to a temper- 90 but desire to be free to use,

ature between that at which the glass melts and that at which the silicate begins to lose its water of hydration; whereby the silicate is dissolved in the molten glass.

3. The method of manufacturing glass which comprises heating a mixture of lass and a micaceous material of high fusibllit to a temperature between that at which the glass melts and that at which the micaceous material begins to lose its water of hydration; whereby the micaceous material is dissolved in the molten glass.

4. The method of manufacturing glass which comprises heating a mixture of glass and comminuted mica to a temperature between that at which the glass melts and that at which the mica begins to lose its water of hydration; whereby the mica is dissolved in the molten glass.

5. The method of manufacturing glass which comprises dissolving a natural silicate of high fusibility in molten vitreous material and maintaining the temperature below that at which the said silicate effioresces.

6. The method of manufacturing glass which comprises dissolving a natural silicate of high fusibility in molten glass and maintaining the temperature below that at which said silicate efiloresces.

7. The method of manufacturing glass which comprises dissolving mica in molten glass and maintaining the temperature be-- lowthat at which the mica eflioresces.

In testimony whereof I hereto affix my signature in presence of two witnesses, this 13th day of August, 1919.

PERCY BRGADBENT CROSSLEY.

Witnesses:

INDU MOHAN BANERJEE, LATIT MOHON BHADRA. 

